The use of a pair of auxiliary side wheels that are to be removably attached on or over the rear axle of a bicycle to control its dynamic lateral instability is well known in the art. The ground stability of bicycles is dynamically enhanced by increased vehicle speed. However, the lateral stability of the bicycle is difficult to maintain at low vehicle speeds, particularly for children and other persons inexperienced in the art of bicycle riding. These side wheels are most often used with children who are learning the basics of riding a bicycle and who still cannot develop sufficient lateral stability when riding their bicycle for the first few times.
Several auxiliary side wheels that exist have the problem of comprising rigid attachment means for linking them to a conventional bicycle. Such rigid attachment means prove to be disadvantageous in several situations. For example, the unevenness of the ground will often result in one of the side wheels being raised above the ground level of the rest of the bicycle wheels, including the opposite side wheel, and therefore not stabilizing the bicycle as it is supposed to. In other cases, the rear bicycle wheel could be elevated with respect to ground level, the rider then losing propulsion capability temporarily. Furthermore, when the rider enters a turn, the lateral stability of the bicycle will again be compromised, as the bicycle will not be able to incline itself properly because of the side wheel's rigid attachment.
The above-described problem has been resolved through a few patents that include suspension means between the bicycle and the auxiliary wheels.
U.S. Pat. No. 5,492,354 issued to RAINEY in 1996 shows training wheels mounted at the end of a coil spring fitted on each side of the rear bicycle wheel axle. The axes of the coil springs are in line with respect to each other and are located with an offset below and parallel to the rear wheel axle. Thus the training wheels can be pulled backward against the action of the spring even though the coil spring allows their upward movement. Consequently, a drawback of the apparatus disclosed by RAINEY is that friction resulting from uneven terrain may cause one of the two auxiliary wheels to be pulled backwards, and thus resist forward movement making the bicycle turn inadvertently.
U.S. Pat. No. 2,450,979 issued to MOLLER in 1948 discloses another coil spring suspension system for mounting to an auxiliary wheel assembly on a bicycle rear wheel axle. A L-shaped bracket interconnecting both axles keeps the auxiliary wheel axle downwardly offset from the bicycle gearwheel axle. An upwardly inclined, adjustable length coil spring member movably interconnects the hub of the auxiliary wheel to the bicycle rear wheel axle. The MOLLER apparatus would be expensive to manufacture and susceptible to damage because of its numerous separate components.
U.S. Pat. No. 2,793,877 issued to MEIER in 1957 shows an apparatus which uses a generally L-shaped flat spring blade to mount an auxiliary wheel to a location near the rear bicycle rear wheel. The vertical leg of the L-spring blade and that of a second, rigid L-blade are anchored to the bicycle rear wheel axle. An adjustable length vertical member movably connects the transverse leg of the rigid blade overlying the transverse wheel axle leg of the flexible blade to the latter flexible blade. The relative angular play between the auxiliary wheel axle and the bicycle rear wheel axle is quite limited with this apparatus, since the auxiliary wheel axle motion is limited to a downward motion relative to the horizontal leg of the rigid L-blade which remains parallel to the bicycle rear wheel axle. In order to prevent travel of the blade spring in a horizontal plane either forward or backward, a second rigid blade and legs are required when using the blade spring.
In all of the above noted patents, the auxiliary wheels are functional, but they are complicated at different levels in that they either require a plurality of parts for installing the side wheels on the bicycle (e.g. brackets, spindles, springs, etc.) or additional manufacturing requirements when a single structural part is used which increase the cost of manufacturing the product.